python formula method doubt : eggs + packages + buildout + section tests + svn

i have several python projects share common modules. until now, i've ... ahem ... retaining churned copies common formula synchronizing hand. nonetheless i'd clearly move something else.

it looks me now, zc.buildout maybe i need. i speculation i should doing putting any reusable member component removed egg, following controlling buildout arrange projects.

i'm also pondering any sole module, i should put unit-tests removed package egg, i'm also installing copies component's unit-tests each project. i wholly wish unit-test place where library developed, where it's only being used.

so maybe i wish something this

projects
  lib1
    tests
    code
  lib2
    tests
    code
  app1
    tests 
    appcode
  app2
    tests
    appcode

etc.

where both app1 app2 individualist applications possess formula tests, nonetheless also including controlling both lib1 lib2. lib1/test, lib1/code, lib2/test, lib2code, app1, app2 removed eggs. does sound right?

however, i confused. i assume i arise app1, i wish buildout lift copies lib1, lib2 app1 removed operative office rather put copies libraries underneath app1 directly. nonetheless does work svn source-control? operative office boldly assembled buildout, can't live svn office i check changes behind repository?

have i misunderstood buildout meant used? i improved going totally opposite approach? brew source-control module-reuse between projects?

update : interjection twin who've now answered question. i'm experimenting some-more this.